Tropical Depression FIFTEEN

ZCZC MIATCDAT5 ALL
TTAA00 KNHC DDHHMM
TROPICAL DEPRESSION FIFTEEN DISCUSSION NUMBER   1
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL   AL152007
500 PM EDT THU OCT 11 2007
 
THE AREA OF LOW PRESSURE IN THE CENTRAL ATLANTIC EAST OF BERMUDA HAS
BEEN MAINTAINING STEADY DEEP CONVECTION NEAR THE CENTER FOR ABOUT
12 HOURS OR SO...AND DVORAK CLASSIFICATIONS FROM TAFB AND SAB AT
18Z HAVE RISEN TO T1.5.  ON THIS BASIS...ADVISORIES ARE INITIATED ON
TROPICAL DEPRESSION FIFTEEN.  AN ASCAT PASS NEAR 14Z SUGGESTS THAT
MAXIMUM WINDS ARE NEAR 30 KT.
 
THE INITIAL MOTION IS 075/14.  THE CYCLONE IS LOCATED TO THE EAST OF
AN UPPER LOW THAT IS PRODUCING STRONG SOUTHWESTERLY FLOW OVER THE
CENTER.  GLOBAL MODELS SUGGEST THAT THE SOUTHWESTERLY FLOW WILL BE
REPLACED BY EVEN STRONGER NORTHERLIES OVER THE NEXT 24-36 HOURS. 
IN THIS STRONG SHEAR ENVIRONMENT...THE MOTION OF THE CYCLONE WILL
DEPEND ON HOW MUCH CONNECTION THE CENTER MAINTAINS WITH THE FLOW
ALOFT.  THE 12Z RUNS OF THE GLOBAL MODELS SEEM TO HAVE ALREADY
SEPARATED THE CENTER FROM THE DEEP CONVECTION...WHICH OF COURSE
HASN'T HAPPENED YET.  AS A RESULT...MY FORECAST TAKES THE CYCLONE A
LITTLE FARTHER EAST THAN MOST OF THE OBJECTIVE GUIDANCE.  BEFORE
TOO LONG...HOWEVER...THE SHEAR SHOULD PREVAIL...LEAVING THE
LOW-LEVEL CIRCULATION BEHIND TO MEANDER UNTIL THE NEXT FRONTAL
SYSTEM ARRIVES IN THE AREA IN ABOUT TWO DAYS.

WITH STRONG SHEAR FORECAST TO PERSIST OVER THE CYCLONE...LITTLE OR
NO STRENGTHENING IS EXPECTED.  THE OFFICICAL FORECAST IS IN GOOD
AGREEMENT WITH THE SHIPS AND HWRF GUIDANCE.  THE GFDL DOES BRING
THE DEPRESSION TO STORM STRENGTH...BUT THERE IS ONLY A VERY SHORT
WINDOW OF OPPORTUNITY FOR THIS TO OCCUR. 

IT IS POSSIBLE THAT SOME OF THE LOW-LEVEL VORTICITY FROM KAREN'S
REMNANTS HAS PLAYED A ROLE IN THE GENESIS OF THIS CYCLONE. 
HOWEVER...THE EVIDENCE IS NOT STRONG ENOUGH TO ATTACH THAT NAME TO
THIS SYSTEM.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INITIAL      11/2100Z 30.1N  50.5W    30 KT
 12HR VT     12/0600Z 30.1N  49.0W    30 KT
 24HR VT     12/1800Z 30.0N  48.0W    30 KT
 36HR VT     13/0600Z 30.0N  48.0W    25 KT...REMNANT LOW
 48HR VT     13/1800Z 31.0N  47.5W    25 KT...REMNANT LOW
 72HR VT     14/1800Z...DISSIPATED
 
$$
FORECASTER FRANKLIN
 
NNNN